As times continue to change, bicycles have transformed from transportation means to entertainment and workout tools of the modern people. Along with the progressing technologies, a bicycle may be installed with numerous sensors, which allow a rider to record riding data such as the pedaling speed, riding mileage, pedaling frequency and pedaling force while the rider rides the bicycle. Through data analysis, the rider may learn his/her physical conditions.
For example, the U.S. Pat. No. 8,689,645, “Bicycle Crank Arm”, discloses a bicycle incorporating a pedaling force sensor. The disclosure includes a crank body, a reference member and a sensor. The reference member is attached to the crank body. The sensor is attached to at least one of the crank body and the reference member. When the rider pedals, the crank body receives the force and becomes curved to cause a change in the distance between the crank body and the reference member, hence obtaining the size of the pedaling force.
Further, in known technologies, a sensor may be used to detect an angular position of a pedal on a circular motion. In conjunction with the distance between the crank body and the reference member, the size of the pedaling force and the relationship between the pedaling force and the pedaling position may be calculated, so as to provide a training reference for adjusting the pedaling force for the bicycle rider.
When the pedal is pedaled based on the foregoing method, corrections are made according to the angular position of the pedal performing a circular motion and the force applied on the crank body. It should be noted that, a force is applied by the user upon the pedal of the bicycle in a circular manner, and the tangential direction of the circumference in fact accounts as an effective force. In known technologies, the measurement of the angle of the pedal plane of the pedal is overlooked, in a way that the real effective pedaling force of the rider cannot be truly calculated. Further, to satisfy a sense of accomplishment, a rider may usually value more highly on the riding mileage and riding speed, and neglect whether the pedaling angle, which is the most important, is accurate. Over an extended period of time, sports injuries of the feet or other parts may likely be caused, resulting in reduced riding efficiency. Therefore, there is a need for a solution that detects an angle relationship between a pedal plane and the ground surface to calculate a real pedaling force and to reduce sports injuries.